MORE TECHNICAL QUESTIONS

What is JavaScript ?

Posted:
JavaScript is a platform-independent, event-driven, interpreted programming language developed by Netscape Communications Corp. and Sun Microsystems. Originally called LiveScript (and still called LiveWireTM by Netscape in its compiled, server-side incarnation), JavaScript is affiliated with Sun’s object-oriented programming language JavaTM primarily as a marketing convenience. They interoperate well but are technically, functionally and behaviorally very different.

Where can I find online documentation for JavaScript?

Posted:
ECMAScript (ECMA-262) has since June 1997 been the official scripting standard for the Web. It is documented at: http://www.ecma.ch/stand/ecma-262.htm

Where is the official bug list for JavaScript?

Posted:
Netscape maintains a page of JavaScript Known Bugs in its online Navigator Release Notes. Unfortunately, according to guru Danny Goodman, “this list is not complete,” and we know of no definitive, well-maintained alternative.

What are the language’s basic entities?

Posted:
As in most object-oriented, event-driven programming languages, there are four distinct entities in JavaScript: * OBJECTS. A discussion of objects is beyond the scope of this FAQ (see the section “Objects and the Web” in Intranet Journal’s Intranet FAQ for background). It’s impossible to understand JavaScript without knowing the following essentials, however: 1. everything you can control [...]

How does JavaScript model the world?

Posted:
This question goes to the heart of any OOPS [Object-Oriented Programming System]. The abbreviated answer given here — lengthy as it is — omits important differences between the Netscape and Microsoft broswer object models, and between various versions of JavaScript.

How is JavaScript syntax like C / C++?

Posted:
The languages have enough in common to make learning one easy if you know the other. By the same token, the differences are subtle enough to trip up those proficient in both. Here’s a short list comparing C and JavaScript: * Terminating JavaScript command lines in semicolons is optional; in C it’s mandatory. Recommended practice is [...]

How do I … with JavaScript/JScript … embed JavaScript in a web page?

Posted:

How do I … with JavaScript/JScript … use the same variable name several times in a script?

Posted:
By default all variables in JavaScript are global, meaning they retain their values everywhere in a scripted web page. To make a variable local to a block (such as a function), declare it with the keyword var. Here’s a n example: // here ‘i’ is a global counter variable that could, if reused // elsewhere in this [...]

How do I …with JavaScript/JScript … use quotation marks when scripting?

Posted:
There are two types of quote mark in JavaScript, the single-quote (’) and double-quote (”). Either can be used to delimit a string literal, or sequence of characters. For example: myDblQString = “This string is surrounded by double-quote marks.”; mySngQString = ‘This string is surrounded by single-quote marks.’; However, since HTML itself makes extensive use of double-quotes within [...]

How do I …with JavaScript/JScript … submit forms by e-mail?

Posted:
The most reliable way is to use straight HTML via a Submit style button. Set the ACTION of the to a mailto: URL and the ENCTYPE attribute to “text/plain”. For security reasons, the form.submit() method does not submit a form whose ACT ION is a mailto: URL. Microsoft Internet Explorer 3.0x does not e-mail forms [...]

What?s relationship between JavaScript and ECMAScript?

Posted:
At best, a client-side script can show the visitor how many she has been to the site (storing the count in a local cookie). A count of total hits to the server requires a server-side program.

What?s relationship between JavaScript and ECMAScript?

Posted:
ECMAScript is yet another name for JavaScript (other names include LiveScript). The current JavaScript that you see supported in browsers is ECMAScript revision 3.

What are JavaScript types?

Posted:
Number, String, Boolean, Function, Object, Null, Undefined.

How do you convert numbers between different bases in JavaScript?

Posted:
Use the parseInt() function, that takes a string as the first parameter, and the base as a second parameter. So to convert hexadecimal 3F to decimal, use parseInt (”3F”, 16);

What is negative infinity?

Posted:
It?s a number in JavaScript, derived by dividing negative number by zero

What boolean operators does JavaScript support?

Posted:
&&, || and !

What does “1″+2+4 evaluate to?

Posted:
Since 1 is a string, everything is a string, so the result is 124.

How about 2+5+”8″?

Posted:
Since 2 and 5 are integers, this is number arithmetic, since 8 is a string, it?s concatenation, so 78 is the result.